Hearing aid



H. LIEBEF'? HEARING AID m 5, was.

Filed Aug. 25, 1934 2 Sheets-Sheet l INVENTOR,

8 m R A ATTORNEY July 5, W38. UEBER 2,122,429

HEARING, AID

Filed Aug. 25, 1934 z sheets -sheet 2 INVENTOR. HUGO 4 M59157? ATTORNEY.

Patented July 5, 1938 UNITED STATES 2,122,429 I HEARING Am Hugo Lieber,New York,

N. Y., assignor to Lieber Patents Corporation, New York, N. Y., acorporation of New York Application August 25, 1934, Serial No. 741,4878 Claims. (01. 119-167) This invention relates to hearing-aids, and ithas among its objects an improved wearable hearing-aid device formaintaining the natural hearing ability of air conducted sound of ahard--of-hearing or deafened person while supplying him at the same time withadditional hearing sensations by bone conduction in an amount sumcientto enable him to hear speech and music like a normal person withoutbeing subjected to strains. v

The invention aims also to provide a wearable hearing-aid device havingtwo hearing-inducing receivers for transmitting hearing-inducing soundvibrations to the hearing center of the user through diiferent paths,the two receivers and their operating circuits being so constructed andcorrelatedv as to supply simultaneously with optimum sound receptionover one path optimum sound reception over the other path.

The foregoing and other objects of the invention will be best understoodfrom the following description of exemplifications thereof, referencebeing had to the accompanying drawings wherein Fig. 1 is a view,partially elevational, and partially diagrammatic, illustrating thearrangement of the elements and the'circuit diagrams of hearing-aidembodying my invention;

Fig. 2 is a top view of the amplifier unit and battery of Fig. 1;

Fig, 3 is an enlarged elevational view of an amplifier unit with thefront cover removed;

Fig. 4 is a sectional view of the amplifier unit along line 4-4 of Fig.3;

Fig. 5 is a sectional view of the amplifier unit along line 5-5 of Fig.4; and

Fig. 6 is an elevational view of the interior the amplifier casing.

Most of the people with defective hearing consist of persons that duringthe first part of their 40 lives heard normally and at a later time,after having acquired the characteristics of normal persons, havethrough sickness or other causes lost their hearing to a lesser orgreater degree. After having adjusted their lives as normal persons,they find themselves handicapped by the This difiiculty has been solvedby the invention of inconspicuous bone-conduction hearingaid receivers.Since the hearing nerves of most deafened persons are intact, soundvibrations imparted by small inconspicuous mechanical bone conductionreceivers are able to produce in most of the deafened persons hearingsensations of an effectiveness equivalent to normal hearing, thusentirely overcoming their handicap.

My invention provides a wearable hearing-aid suitable for concealedinconspicuous wear by a deafened person and constructed to maintain inaction his remaining normal hearing ability and to simultaneously supplyby bone conduction additional hearing sensations to his hearing centerenabling him to hear like a normal person.

A hearing-aid device of the foregoing type for inducing a satisfactoryamount of hearing sensations in the auditory center of a person and atthe same time maintain in action his residual hearing ability is shownin Fig. 1 of the drawings. It comprises a battery unit iii, atransmitter Ii, an air conduction receiver l2, a bone conductionreceiver l3, anamplifier unit I4, and an interconnecting cord 15. Thebattery l0 may be in the form of a fiat dry cell, or a similar source'of "supply generally used in portable hearing-aids. 0n the top of thebattery unit are two terminal sleeves l8, ll of opposite polarity,sleeve it, for instance, being positive and sleeve l1 negative.

The transmitter unit ll comprises two microphones 2 I, 22 comprisingcarbon diaphragms and carbon buttons holding a plurality of ,carbongranules to vary the resistance therebetween in accordance with soundvibrations acting on the diaphragm. Mounted within the transmitter unitis a control unit 23 comprising a resistor 24, a stationary contactmember 25, a contact rod 26 and a movable contact member 21 slidablymounted on 'the contact rod, and movable between a position where themovable contact member makes a conductingconneetion between the resistor24, contact member 25 and contact rod 26, cutting out the resistor asfitis moved in one way, and interrupting the connection be- \tween theseveral elements as it is moved the opposite way. Three plug contacts 28connected to the resistor 24, the carbon button of one microphone, andthe rod 26 are engaged by three plug pins 2|, 22, 33 of a plug 34provided at one end of cord ii. The two microphones 2i and 22 areconnected in series between the stationary contact member 25 and theplug terminal 28 engaging the plug pin 32.

The air conduction receiver may be in the 5 form of a small telephonereceiver as disclosed, for instance, in Patent No. 1,913,318, and has anactuating winding 31 which is connected to plug pins 38 at the end of acord branch 33-. The bone conduction receiver 3 is likewise of smallsize suitable for inconspicuous wear, for instance, as shown in PatentNo. 1,940,553, and has an actuating winding 4| which is connected toplug pin terminals 42 at the end of a cord branch 43. The amplifier unitI4 is shown in detail in Figs. 2 to 6. It comprises a fiat,substantially rectangular housing 45 of insulating material, forinstance, a phenolic condensation product, and is small insize to fitthe space above the battery and permit its concealed wear in conjunctionwith the battery unit. Back of the removable front wall 48 of thehousing are mounted two small microphone amplifier units t1 and 48,which are preferably of the type shown Reissue Patent No. 19,2461,

The two microphone units have each a carbon granule chamber having acarbon electrode 5|, a carbon diaphragm electrode 52 movably heldopposite the open side of said chamber for varying the resistance pathof the carbon granules, and an electromagnetic vibrator having anactuating winding 53 for passing sound-frequency current oscillationssupplied thereto by the transmitter The elements of each microphoneamplifier 41 and 48 may be assembled into self-contained units as shownin Figs. 5 and 6 and in Reissue Patent No. 19,246. The actuating winding83 has one end connected to the metallic clamping member 54 thereof, theother end of the winding having on its outer surface a resilient contactstrip 55 as shown in Fig. 5. Each amplifier microphone unit has asupporting member 51 by means of which it is attached within the housingby screws 58 threadedly engaging ledges 59 extending from the lateralwalls of the housing.

In the bottom wall 88 of the housing are mounted two downwardlyextending current supply pins 8|, 62 arranged to fit into the sleevesl8, H of the battery and establish an electrical as well as a mechanicalengagement between the housing 45 and the battery unit. The supplyterminal pins 8| and 82 have inward extensions 83 threaded at their endsand held firmly in place by means of nuts 54. Two pairs of similar plugpins 85, 88, 51, 88 are similarly mounted on the opposite side of thehousing and held firmly thereon by inward extensions clamped by nuts 5-9threaded thereon. The supply pin 8| has secured underneath its holdingnut 84 a contact strip 1| of conducting material which runs along theinner wall of the housing and has its end clamped underneath the nut ofthe contact pin establishing an electrical connection therewith. In asimilar way a contact strip 12 of resilient material, such as phosphorbronze, is mounted on the interior side. of the rear wall of the housingand has on its lower end a lateral extension which is held clampedunderneath the nut 84 oi the second supply pin 82.

An additional contact strip 15 of resilient material, having one endheld clamped underneath the nut 89 of contact pin 88, has its other endformed into a bent-over rectangularly-shaped contact portion 16 heldspaced between two inward housing wall extensions 11 and arrangedto makecontact with the contact strips 55 provided on the amplifier winding 53as shown in Fig. 5.

Upon insertion of the two assembled microphone units 41 and 58 intoplace within the housing as shown in Fig: 3, each unit has its terminalsconnected as follows: The holding strip 54 cf the and the flexiblecontact strips 18, 19, having clamped ends held under the nuts 89 of thecontact pins 81, 83, establish conducting connections between these pinsand the microphone chamber 5| and thereby establishing conductingconnections between the carbon electrodes 5|. The housing is then closedand the interior sealed by mounting the cover 45 in place.

The cord |5 has at its lower end two branches 8|, 82 terminating sockets83, 84, making resilient detachable connections with the terminals 85 to88 on the opposite sides of the housing, and establishing by its cordleads 88 and 81 of cord branch 9| connections between amplifier housingternnnals 85, 88 and transmitter plug pin terminals 3|, 82,respectively, and by its cord leads 81 and 88 of cord branch 82 andcord'branches 38, 45 connections between amplifier housing terminais 61,88 and transmitter plug pin terminals 33, the cord leads 81 and 88,including in series the two receiver windings 31, 4|, and the rheostats98, 99. The housing is also provided with blocks 85 underlying the plugsockets 83, 8% to protect them against extemai strains and permit easyremoval of the amplifier unit.

By connecting the several elements of the hearing-aid in the way shownin Fig. 1, a primary and a secondary amplifier circuit is establishedfor each receiver, parts of the circuits including the microphonetransmitter II with the control unit 23 and the battery being common tothe circuits of both receivers.

The primary circuit for both receivers extends from the positive supplypin terminal 5| of the amplifier engaging positive battery terminal l8,through connector 1 I, amplifier terminal 85, cord lead 88, transmitterterminal 8| in series through the rheostat contact members 28, 21, 25,through the series connected transmitter microphones 2|, 22, transmitterterminal 32, cord lead 81, arnplifier terminal 88, connector 15, andtherefrom along parallel paths through the windings 58 of the twoamplifiers and connector 12 to the negative supply pin terminal 82engaging the negative terminal H of the battery,

The secondary circuit for both receivers extends i'rom the positiveamplifier supply terminal I8 over the common circuit portion, throughconnector 1|, amplifier terminal 85, cord lead 88, transmitter plugterminal 3|, rheostat rod 25, rheostat'c-ontact 21, resistor 24, totransmitter plug terminal 38. and therefrom in parallel circuits by wayof cord loads 88, 88 through the receiver windings 31, 4|, receiverrheostats 88, 88. over cord branch 82, through amplifier terminals 81,88, connectors 18, 19, the two amplifier nal 82.

The two cord branches 88, 43 leading to receivers l2 and I3 are ofsumcient length to permit} application of the air conduction receiver l2to the ear on one side of the head of the listener;

and 01' the bone receiver l3 to the mastoid bone may be independentlyincreased or decreased by adjusting the two independently adjustablereceiver rheostats 98, ,99 connected in each of the two receiver leads.Once the relation of the sound intensities of the two receivers has beenadjusted, the common rheostat 24 may be used to simultaneously increaseor decrease the sound intensity of the two receivers while maintainingsubstantially the same relation between their sound intensities.

There are many deafened persons that hear like normal persons by boneconduction who desire to maintain a small remnant of normal hearingability in use, although this remnant is insufficient to supply themwith satisfactory hearing even when using air-conduction telephone aids.The hearing-aid describedabove enables such deafened persons to makefull use of his remnant hearing ability and at the same time supplieshim with enough bone conduction hearing sensations to make him hear likea normal person. By means of this hearing-aid, a person of impairedhearing, whose normal hearing ability cannot be fully restored by an airconduction instrument, can adjust the intensity of the sound that he isdesirous to hear to the maximum, value that is usefuLin helping him tohear. He may make-thisadjustment while the circuit through thebone-conduction receiver includes substantially thefull amount of itsresistance so as to restrict the hearing sensation to the action of theair-condition receiver. After having adjusted the rheostat of theair-conduction receiver to the maximum value helpful in hearing, butinsumcient for satisfactory hearing, he then adjusts the rheostat in thereceiver circuit to a point at which he receives additional soundsensations by bone conduction in an amount sufllcient to make him hearlike a normal person. v

The instrument may be adjusted while the user listens to persons closeto him and a relatively small sound intensity is sufiicient forunderstandingtheir speech. The common rheostat which controls theintensity in both circuits may be held in a position at which the ratioof hearing effects produced by the two receivers is made sufilcient tohear a nearby person under the full utilization of the natural hearingability of the user. He can then readily use the instrument to hearpersons that are far away, or to use the instrument in a theatre wherehe needs a greater volume of sound for satisfactory hearing, by cuttingout a part or all of the resistance in the 'common circuit, the ratio ofthe two currents in the branches of the two receivers being maintainedsubstantially the same at the higher intensities and thereby enablingfull utilization of his remaining natural hearing ability throughout theentire range of the instrument.

The exemplification of the invention described above will suggest tothose skilled in the art It is accordingly desired that the appendedclaims be given a construction commensurate with the scope of theinvention within the art.

.The features of the invention described above are susceptible to manymodifications that will suggest themselves to those skilled in the art.

I'claim:

1. In a wearable hearing-aid device, a microphone transmitter, a firsthearing-inducing receiver for inducing hearing through one soundconducting path of the user, a second hearinginducing receiver forinducing hearing through another sound conducting path of the userhaving different characteristics than said first sound conducting path,each of said receivers having an actuating winding and a lead includingsaid winding, a battery having two terminalsof opposite polarity, awearable amplifying un'it having two supply terminals detachablyengaging said battery terminals, said leads and said transmitter beingconnected to said amplifying unit for simultaneously supplyingsound-frequency currents induced by said transmitter toreceiver windingsof said two receivers, said receivers and the elements included in thecircuits ofsaid leads being constructed and correlated to operate withcharacteristics required in order to impart to the deafenedsimultaneously with optimum sound reception with said first receiver acorrelated optimum sound reception with said second receiver, and meansfor adjusting the total sound reception imparted to the auditory centerof the deafened.

2. In a portable hearing-aid device for a deafened, a microphonetransmitter, an air-conduction receiver having an actuating winding anda lead including said winding, a boneconduction receiver having anactuating winding a'nd a lead including said winding, a battery havingtwo terminals of opposite polarity, a portable amplifying unit havingtwo Supply terminals detachably engaging said battery terminals, saidleads and said transmitter being connected to said amplifying unit forsimultaneously supplying sound-frequency currents induced by saidtransmitter to said receiver windings, said receivers and the elementsconnected in the circuits of said leads being constructed and correlatedto operate with characteristics required for correlating the outputs ofsaid receivers within the range of audible sounds to impart to thedeafened simultaneously with optimum sound reception with saidair-conduction receiver a correlated optimum sound reception with saidboneconduction receiver.

3. In a portable hearing-aid device for a deafened, a microphonetransmitter, an air-conduc-' tion receiver having an actuating windinganda leadincluding said winding, a bone-conduction receiver having anactuating winding and a. lead terminals of opposite polarity, a portableamplifying unit having two supply terminals detachably engaging saidbattery terminals, said leads and said transmitter being connected tosaid amplifying unit for simultaneously supplying soundfrequencycurrents induced by said transmitter to said receiver windings, means inthe circuits of said leads for correlating the outputs of said receiverswithin the range of audible sounds to conduction receiver having anactuating winding and a lead including said windings. battery having twoterminals of opposite polarity, a-portable amplifying unit having twosupply terminals detachably engaging said battery terminals, one

including said winding, a battery having two of said receiver leads andsaid transmitter being connected to said amplifier unit for supplying.tion receiver having an actuating winding and a I lead including saidwinding, a bone-conduction receiver having an actuating winding. and alead including said winding, a battery having two terminals of oppositepolarity, a portable amplifying unit having two supply terminalsdetachably engaging said battery terminalacne-ot said receiver leads andsaid transmitter being connected to said amplifier unit for supplyingamplified sound-frequency currents induced by said transmitter to theassociated receiver, the other of said receiver leads being connectedparallel to the input circuit of said amplifier, means in the circuitsof said leads for'- correlating the outputs of said receivers within therange of audible sounds to impart to the deafened simultaneously withoptimum sound reception with said air-conduction receiver a correlatedoptimum sound reception with said bone-conduction receiver, and meansfor independently adjusting the total sound reception iinparted to theauditory nerve center of the deafened while maintaining a predeterminedoptifnum correlation between the sound receptions imparted by theindividual receivers. v

I 6. In aportabie hearing-aid device for a deafened, a microphonetransmitter, an air-conduction receiver having an actuating winding anda lead including said winding, a bone-conduction receiver having anactuating winding and a lead including said winding, a battery havingtwo terminals of opposite polarity, and a portable amplifying unithaving two supply terminals cletach ably engaging said batteryterminals, said boneconduction receiver lead and said transmitter beingconnected to said amplifier unit for supplying amplified soundfrequencycurrents induced by said transmitter to the associated receiver;

.timum correlation between the sound receptions said air-conductionreceiver lead being connected parallel to the input circuit oi. saidamplifier.

7. In a portable hearing-aid device for a deafened, a microphonetransmitter, an air-conduction receiver having an actuating winding and5 a lead including said winding, a bone-conduction receiver having anactuating winding and a lead including said winding, a battery havingtwo terminals of opposite polarity, a portable amplifying unit havingtwo supply terminals detach- 10 ably engaging said battery terminals,said bone conduction receiver lead and said transmitter being connectedto said amplifier unit for supplying amplified sound-frequency currentsinduced by said transmitter to the associated re- 15 ceiver, saidair-conduction receiver lead being connected parallel to the inputcircuit of said amplifier, and means in the circuits of said leads forcorrelating the outputs of said receivers within the range of audiblesounds to impart to the 20 deafened simultaneously with optimum soundreception with said air-conduction receiver a correlated optimum soundreception with said boneconduction receiver.

8. In a portable hearing-aid device for a deaiened, a microphonetransmitter, an air conduction receiverflhaving an actuating winding anda lead including saidWTiKdlifia?bone-conductionreceiver having anactuating winding and a lead including said winding, a battery havingtwo 3;) terminals of opposite polarity, a portable amplifying unithaving two supply terminals detachably engaging said battery terminals,said boneconduction receiver lead and said transmitter being connectedto said amplifier unit for supplying amplified sound-frequency currentsinduced by said transmitter to the associated receiver, saidair-conduction receiver lead being connected parallel to the inputcircuit of said amplifier, means in the circuits of said leads for 40correlating the outputs of said receivers within the range of audiblesounds to impart to the deafened simultaneously with optimum soundreception with said air-conduction receiver a correlated optimum soundreception with said bone-conduction receiver, and means forindependently adjusting the total sound reception imparted to theauditory nerve center of the deafened while maintaining a predeterminedopimparted by the individual receivers. I

HUGO LIEBER.

